Jacks are compressed silvery fishes with a pair of dorsal and anal fins, stiff, forked tails and narrow caudal peduncles often protected by a hard ridge of scales known as scutes.  In most species the first anal fin composed of three short spines is embedded in the skin just behind the anus.  

These fishes are carnivores that may form schools or aggregations in a wide range of habitats including estuaries, bays, reefs, and the open sea.  Some species will hunt opportunistically by trailing other carnivores as they forage including eels, sharks, and marine mammals.

Most species are valuable food and sport fishes but large trevallies have been depleted in most areas due to overfishing.  Large Carangids feed heavily upon reef fishes and are the most-likely carriers of ciguatoxin, which causes serious illness in mammals if eaten.

Many species have long-lived larvae and occur around the world in warm and temperate waters.

Phoenix, Midway, 50 feet

Phoenix, Midway, 50 feet

Uncommon along reef dropoffs.  Restricted to deep water in Hawaii except at Midway.  Dark green with concave forehead and black scutes.  Attains 32 inches.  Worldwide in warm seas.

Juvenile, Angel Ledge mooring, Midway

Juvenile, Angel Ledge mooring, Midway

Juvenile, with Thysanostoma jelly, Moku Manu, Oahu

Juvenile, Chromis mooring, Midway

Juvenile, Kona Coast, Hawaii

Thysanostoma jelly, Kona Coast, Hawaii

Adults rarely encountered, preferring deep reefs below normal diving depths.  Juveniles seen with floating objects or large jellies.  Interior of mouth is white.  Adults are broadly rounded and dark in color.  Attains 20 inches.  Worldwide in warm seas.  Uraspis reversa & U. secunda are synonyms.

Portlock, Oahu

Portlock, Oahu

Ko'olina Lagoon, Oahu

Uncommon over soft bottoms in harbors, bays, and deeper water.  Wedge-shaped body with steep forehead and lacking first dorsal fin.  Juveniles have elongated streamers.  Reaches 4.5 feet and 60 pounds.  An excellent food fish.  Worldwide in warm seas.

Phoenix, Midway, 50 feet

Inhabits open water adjacent to reefs and islands.  Uncommon in Hawaii.  Green above with blue and yellow stripes, no scutes.  Attains 4 feet.  Worldwide in warm seas.

Juvenile, Angel Ledge buoy, Midway

Pacific Beach Hotel, Oahu

Fish Hole, Midway, 40 feet

Common in deep water, often ventures into shallow water to prey upon fishes.  Brown above with yellow lateral stripe and dark diagonal bar through large eyes.  Often causes ciguatera poisoning.  Attains 6 feet and at least 150 pounds.  Worldwide in warm seas.

Cabo Pulmo, Baja California, Mexico, 100 feet

Midway Atoll

Midway Atoll

Inhabits coastal waters.  Rarely found around Midway, it is common in continental waters.  Green above with yellow lateral stripe and fins.  Scutes absent.  Attains at 5 feet & 115 pounds.  Excellent food and game fish.  Worldwide in subtropical and warm temperate waters.

Kailua-Kona, Hawaii, 20 feet

Kailua-Kona, Hawaii, 20 feet

Abundant in coastal waters.  Tapering body, pointed snout, dark spot at gill opening.  Feeds upon zooplankton and preyed upon by pelagic fishes.  An important food and bait fish in Hawaii.  Attains 12.5 inches.  Worldwide in warm seas.

Juvenile, Haleiwa Trench, Oahu, 5 feet

Sharks Cove, Oahu, 10 feet

Pitt Stop, Midway, 15 feet

Sharks Cove, Oahu, 10 feet

Seasonally abundant in quiet bays and coastal waters.  Large eyes, dark spot at gill opening.  Feeds upon zooplankton and preyed upon by large jacks and sharks.  An important food fish in Hawaii.  Attains 11 inches.  Worldwide in warm seas.

North Beach, Midway, 10 feet

Hanauma Bay, Oahu, 10 feet

Uncommon on sandy reefs in small groups.  Faint dark bars on a oval body.  Attains 21 inches.  Excellent food fish.  Indo-Pacific including Hawaii.

Moku Manu, Oahu, Pelagic

Pitt Stop, Midway, 40 feet

Uncommon on sandy reefs.  Attains 28 inches.  Indo-Pacific & the Tropical Eastern Pacific, including Hawaii.

Subadult, Hanauma Bay, Oahu, 4 feet

Fish Hole, Midway, 20 feet

Pitt Stop, Midway, 20 feet

Courting male, Pitt Stop, Midway, 20 feet

Pitt Stop, Midway, 20 feet

Pearl & Hermes Reef, NWHI, 10 feet

Pearl & Hermes Reef, NWHI, 10 feet

Gardner Pinnacles, NWHI, 25 feet

Quite rare in areas with fishing activity, it is the dominant species in terms of biomass in the Northwestern Hawaiian Islands except Midway where the population was depleted due to sport fishing.  Courting males may appear black.  Attains at least 5 feet and 150 pounds.  Often causes ciguatera poisoning.  Indo-Pacific including Hawaii.

Hanauma Bay, Oahu, 5 feet

Hanauma Bay, Oahu, 25 feet

Hanauma Bay, Oahu, 25 feet

Opportunistic hunting, Sharks Cove, Oahu

Most common trevally in nearshore waters.  Blue fins and spots on body, pectoral fins yellow.  Attains 39 inches and 100 pounds.  Excellent food fish but larger ones may cause ciguatera poisoning.  Indo-Pacific & Tropical Eastern Pacific including Hawaii.

Pacific Beach Hotel, Oahu

Pacific Beach Hotel, Oahu

Schooling young found in protected areas, adults are rare.  Nocturnal reef predator.  Elongate body, large eyes, black spot at upper edge of gill opening, white fin tips.  Attains 33 inches.  Less palatable than other species.  Indo-Pacific & Tropical Eastern Pacific including Hawaii.

Juvenile, Fish Hole, Midway, 30 feet

Juveniles, Fish Hole, Midway, 30 feet

Phoenix, Midway, 50 feet

Pacific Beach Hotel, Oahu

Pacific Beach Hotel, Oahu

Pacific Beach Hotel, Oahu

Uncommon over sand or mud in bays and harbors.  Juveniles are bright yellow with bold black bars, adults become pale and acquire black blotches, lips thick and toothless.  Feeds upon buried shellfish.  Attains 4 feet.  Excellent food fish.  Indo-Pacific, tropical Eastern Pacific & Hawaii.

Hanauma Bay, Oahu, 10 feet

Hanauma Bay, Oahu, 10 feet

Maui

Fairly common in the water column near reefs.  Shiny, leathery skin with bright spots and black tipped dorsal fin and dark caudal fin lobes.  Scutes absent.  Fin spines are venomous.  Attains 27 inches.  Dried skin used in fishing lures.  Indo-Pacific including Hawaii.

Yawatano, Izu, Japan, 20 feet

Yawatano, Izu, Japan, 20 feet

Rock Quarry, Catalina Island, California, 10 feet

Grand Bahama, 45 feet

Inhabits coastal waters, schools sometimes encountered on reefs.  Tips of caudal fin are black, small black mark on upper gill cover.  Attains 23 inches.  An excellent food fish.  Nova Scotia to Bermuda & Brazil.

Grand Bahama, 45 feet

Inhabits coastal waters and reefs in small aggregations.  Caudal fin is yellow.  Attains 30 inches.  New Jersey to Bermuda and Brazil.

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